Solvent‐Controlled Topological Evolution from Nanospheres to Superhelices

Abstract

Supramolecular assemblies with diverse morphologies are crucial in determining their biochemical or physical properties. However, the topological evolution and self‐assembly intermediates as well as the mechanism remain elusive. Herein, a dynamic morphological evolution from solid nanospheres to superhelical nanofibers is revealed via self‐assembly of a minimal l‐tryptophan‐based derivative (LPWM) with various mixed solvent combinations, including the formation of solid nanospheres, the fusion of nanospheres into pearling necklace, the disintegration of necklace into short nanofibers, the distortion of nanofibers into nanotwists, and the entanglement of nanotwists into superhelices. It is found that the breakage of intramolecular H‐bonds and reconstruction of intermolecular H‐bonds, as well as the variation of aromatic interactions and hydrophobic effects, are the key driving forces for topological transformation, especially the dimensional evolution. The nanospheres and nanofibers demonstrate discrepant behaviors towards mouse neural stem cell (NSC) differentiation that compared with negligible impact of nanospheres scaffold, the nanofibers scaffold is favorable for NSC differentiation into neurons. The remarkable dynamic regulation of assembly process, together with the NSC differentiation on twisted nanofibers are making this system an ideal model to interpret complex proteins fibrillation processes and investigate the structure–function relationship.

Effect of Stereochemistry on Chirality and Gelation Properties of Supramolecular Self‐Assemblies

“…To date, various chiral nanostructures, such as helical ribbons, [19–21] twisted nanofibers, [22–25] rolled‐up nanotubes, [26–28] and even superhelices, [29–31] have been constructed. For two‐component coassembly systems, chiral amplification usually obeys the following rules: 1) the sergeants‐and‐soldiers (S&S) effect; [32] 2) the majority‐rules (MR) effect; [33] and 3) the diluted MR effect, [34] which is a combination of the other two effects.…”

Rational Fabrication of Multiple Dimensional Assemblies from Tryptophan‐Based Racemate

“…[31][32][33][34] In our previous work, C2 symmetrical molecules with L or Dtryptophan methyl ester arms conjugated to para-disubstituted phenyl (LPWM/DPWM) were synthesized, whose assemblies could be finely controlled by adjusting solvent combinations (Scheme 1). [35] Herein, we concentrated on the morphological regulation of RPWM, a racemate of LPWM and DPWM. External stimuli including solvents and temperature were introduced to modulate the assembled nanostructures.…”

Redox-Driven In Situ Helix Reversal of Graphene-Based Hydrogels

“…60 The stronger aromatic stacking was reported to probably stem from the more compact arrangement in the assemblies. 60,61 From these results, we could speculate that the transformation from intermolecular to interamide hydrogen bonding accompanied by the enhancement of π−π stacking contributed to the helicity inversion. LPFEG would certainly bond with the oxygen functional groups of GO that occupied more hydrogenbonding sites to create a loosely packed arrangement, which generated a right-handed helix.…”

“…Apart from the same XRD patterns arising from their intrinsic backbones, an increasingly stronger diffraction peak at 2θ = 24.98° assigned to d -spacing of 0.35 nm was observed, indicative of enhanced π–π stacking interactions within nanofibers after the treatment with UV irradiation . The stronger aromatic stacking was reported to probably stem from the more compact arrangement in the assemblies. , From these results, we could speculate that the transformation from intermolecular to interamide hydrogen bonding accompanied by the enhancement of π–π stacking contributed to the helicity inversion. LPFEG would certainly bond with the oxygen functional groups of GO that occupied more hydrogen-bonding sites to create a loosely packed arrangement, which generated a right-handed helix.…”